X-ray apparatus with field emission current stabilization and method of providing x-ray radiation therapy

Abstract

The present invention provides apparatus and method for providing a stabilized x-ray output from a field emission x-ray apparatus by monitoring the operating current and adjusting the gap between the anode and cathode to stabilize the output.

1 . An apparatus for producing x-rays with operating current control comprising: 
 a housing;    a probe, said probe including: 
 distal and proximal ends, with said proximal end being attached to said housing; and  
 an outer wall structure defining a hollow interior;  
   an anode attached to said probe at said probe distal end;    a cathode having proximal and distal ends, wherein: 
 said distal cathode end is disposed within said distal probe end and spaced from said anode to create a gap therebetween; and 
 said proximal cathode end is disposed within said housing; and  
 
   a linear translator attached to said proximal cathode end and being provided for moving said cathode toward and away from said anode to adjust said gap and change the operating current;    wherein said probe comprises a conductor and said cathode is insulated from said conductor by an insulator therebetween.    
   
   
       2 . The apparatus of  claim 1  wherein said insulator engages said conductor.  
   
   
       3 . The apparatus of  claim 1  wherein said insulator is spaced from said conductor and said cathode.  
   
   
       4 . The apparatus of  claim 1  wherein said probe defines an axis and said anode includes a target surface disposed at an angle of about 15° to about 60° relative to said probe axis.  
   
   
       5 . The apparatus of  claim 1  wherein said anode is made of pyrolytic graphite and said anode includes a target surface formed from a high nuclear number material.  
   
   
       6 . The apparatus of  claim 5  wherein said insulator is a high strength dielectric.  
   
   
       7 . The apparatus of  claim 5  wherein said insulator is fused quartz.  
   
   
       8 . The apparatus of  claim 1  wherein said insulator is a high strength dielectric.  
   
   
       9 . The apparatus of  claim 1  and further including a cooling system, said cooling system comprising: 
 a pump for pumping a coolant fluid;    a jacket having a hollow interior configured to receive said probe; and    conduits connecting said pump to said jacket;    wherein said pump circulates a coolant fluid through said jacket to cool said probe during operation thereof.    
   
   
       10 . The apparatus of  claim 9  and further including an appliance for stretching tissue, said appliance comprising: 
 a first hollow shaft having first shaft proximal and distal ends, said first hollow shaft configured to receive said probe;    a second hollow shaft having second shaft proximal and distal ends, said second hollow shaft configured to receive said first shaft, said second hollow shaft distal end being secured to said first hollow shaft distal end, said second hollow shaft including a plurality of flexible ribs configured to flex outwardly when said second hollow shaft proximal end is moved toward said second hollow shaft distal end.    
   
   
       11 . An apparatus for providing producing x-rays with operating current control comprising: 
 a housing;    a probe, said probe including: 
 distal and proximal ends, with said proximal end being attached to said housing; and  
 an outer wall structure defining a hollow interior, said outer wall structure including an outer conductive layer and an inner insulative layer;  
   an anode attached to said probe at said probe distal end;    a cathode having proximal and distal ends, wherein: 
 said distal cathode end is disposed within said distal probe end and spaced from said anode to create a gap therebetween; and 
 said proximal cathode end is disposed within said housing; and  
 
   a linear translator attached to said proximal cathode end and being provided for moving said cathode toward and away from said anode to adjust said gap and change the operating current.    
   
   
       12 . The apparatus of  claim 11  wherein said probe defines an axis and said anode includes a target surface disposed at an angle of about 15° to about 60° relative to said probe axis.  
   
   
       13 . The apparatus of  claim 11  wherein said anode is made of pyrolytic graphite and said anode includes a target surface formed from a high nuclear number material.  
   
   
       14 . The apparatus of  claim 13  wherein said insulator is a high strength dielectric.  
   
   
       15 . The apparatus of  claim 11  wherein said insulator is a high strength dielectric.  
   
   
       16 . The apparatus of  claim 11  and further including a cooling system, said cooling system comprising: 
 a pump for pumping a coolant fluid;    a jacket having a hollow interior configured to receive said probe; and    conduits connecting said pump to said jacket;    wherein said pump circulates a coolant fluid through said jacket to cool said probe during operation thereof.    
   
   
       17 . The apparatus of  claim 16  and further including an appliance for stretching tissue, said appliance comprising: 
 a first hollow shaft having first shaft proximal and distal ends, said first hollow shaft configured to receive said probe;    a second hollow shaft having second shaft proximal and distal ends, said second hollow shaft configured to receive said first shaft, said second hollow shaft distal end being secured to said first hollow shaft distal end, said second hollow shaft including a plurality of flexible ribs configured to flex outwardly when said second hollow shaft proximal end is moved toward said second hollow shaft distal end.    
   
   
       18 . A method for providing x-ray radiation therapy to a patient having a tumor, said method comprising: 
 excising the tumor to create a body cavity;    disposing within the body cavity an appliance for stretching the body cavity to a desired configuration;    stretching the body cavity to the desired configuration using the appliance to create a stretched body cavity;    providing an x-ray apparatus for emitting x-rays for x-ray therapy, the apparatus including an elongate probe with a distal end including an anode and a cathode separated by gap;    disposing the apparatus within the stretched body cavity;    irradiating the target with x-rays produced by the apparatus;    monitoring the operating current of the x-ray apparatus; and adjusting the gap between the anode and the cathode at least once to stabilize the x-ray emission to provide the desired irradiation dose rate for the therapy.    
   
   
       19 . The method of  claim 18  wherein the appliance comprises: 
 a first hollow shaft having first shaft proximal and distal ends, said first hollow shaft configured to receive said probe;    a second hollow shaft having second shaft proximal and distal ends, said second hollow shaft configured to receive said first shaft, said second hollow shaft distal end being secured to said first hollow shaft distal end, said second hollow shaft including a plurality of flexible ribs configured to flex outwardly when said second hollow shaft proximal end is moved toward said second hollow shaft distal end.